For carrying a hot workpiece, it is necessary to use a chain conveyor having high resistance to heat or provide a cooling mechanism in a carrying system.
This is because when the carrying conveyor becomes hot, lubricant oil and grease applied to bearings and driving devices used in the carrying conveyor are apt to deteriorate. Accordingly, in the case where lubricant oil and grease are applied to parts to which heat is conducted, the parts have to be cooled so as to make heat conduction difficult. In the case where heat may be conducted to not only lubricant oil and grease but also parts on which heat-sensitive members and devices are mounted, it is also necessary cool them or provide a heat insulating material or member to prevent heat conduction.
Furthermore, the hot carrying conveyor causes such disadvantages that an operator cannot approach it and working environment deteriorates. Accordingly, the carrying conveyor including a cooling device has conventionally been employed.
For instance, there are cooling methods disclosed in Patent Literatures 1 to 3. Patent Literature 1 discloses a cooling technique of a slab carrier. This includes a cooling device for causing cooling water to pass through a roller table serving as a support part of a carrying roller. The cooling device is configured to prevent heat conduction to the roller table and a carriage.
Patent Literature 2 discloses a cooling technique of a carrier. This includes a base placed in a vacuum chamber, a linear table installed on the base, a linear guide for guiding the linear table, and a circulating passage and a heat receiving surface provided in the base. In this configuration, heat from the linear table is conducted to the heat receiving surface. This heat receiving surface is cooled by a cooling medium. Thus, deformation of the linear guide by heat and so on can be avoided.
Patent Literature 3 discloses a cooling technique of a vertical furnace. An in-case cooling medium communication passage is provided to cause a cooling medium to pass through the inside of a wall of a cylindrical case of the vertical furnace. Thus, a measurement device internally provided in the furnace can be protected from external heat.